Multi-particle-size automatic sand screening device

The utility model belongs to the technical field of sand screening equipment, and particularly relates to a multi-particle-size automatic sand screening device which comprises a feeding mechanism, a multi-section screening mechanism, a circulating screening mechanism and a storage mechanism, the multi-section screening mechanism comprises a roller, a rack and a roller driving mechanism, the wall of the roller is formed by sequentially and seamlessly connecting a plurality of sections of screens with different hole diameters, and the multi-section screening mechanism is arranged on the rack. A plurality of sections of screen meshes of the roller are sequentially arranged according to the aperture from small to large, the roller is obliquely and downwards installed on the machine frame in a rotating mode from the fine screen mesh end, discharging valves are arranged on the corresponding sand collecting hoppers below the multiple sections of screen meshes, and the sand collecting hoppers are communicated with th